What two symbols are regulated to indicate the standards for cylinders and cartridges?

The correct response indicates that DOT and TC are the symbols that signify compliance with regulatory standards for cylinders and cartridges. The DOT, or Department of Transportation, oversees the transportation of hazardous materials in the United States, including the specifications for how gas cylinders must be designed, tested, and labeled. The TC, or Transport Canada, serves a similar role in Canada, establishing standards for the transport of dangerous goods, ensuring safety and compliance across both nations.

These symbols ensure that users can trust that the cylinders they are working with meet strict safety guidelines and manufacturing processes which are crucial for preventing accidents and ensuring proper handling of gases. This regulatory framework is essential in maintaining safe operating conditions when dealing with high-pressure and potentially hazardous materials.